[PATCH 2/3] ASoC: SOF: ipc: Add null pointer check for substream->runtime

[Pierre-Louis Bossart]

From: Ajit Kumar Pandey <AjitKumar.Pandey at amd.com>

When pcm stream is stopped "substream->runtime" pointer will be set
to NULL by ALSA core. In case host received an ipc msg from firmware
of type IPC_STREAM_POSITION after pcm stream is stopped, there will
be kernel NULL pointer exception in ipc_period_elapsed(). This patch
fixes it by adding NULL pointer check for "substream->runtime".

Reviewed-by: Ranjani Sridharan <ranjani.sridharan at linux.intel.com>
Signed-off-by: Ajit Kumar Pandey <AjitKumar.Pandey at amd.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>
---
 sound/soc/sof/ipc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sound/soc/sof/ipc.c b/sound/soc/sof/ipc.c
index 8a1eacc7ec5f..12860da1d373 100644
--- a/sound/soc/sof/ipc.c
+++ b/sound/soc/sof/ipc.c
@@ -623,7 +623,8 @@ static void ipc_period_elapsed(struct snd_sof_dev *sdev, u32 msg_id)
 
 	if (spcm->pcm.compress)
 		snd_sof_compr_fragment_elapsed(stream->cstream);
-	else if (!stream->substream->runtime->no_period_wakeup)
+	else if (stream->substream->runtime &&
+		 !stream->substream->runtime->no_period_wakeup)
 		/* only inform ALSA for period_wakeup mode */
 		snd_sof_pcm_period_elapsed(stream->substream);
 }
-- 
2.25.1